A Novel Time-Based Modulation Scheme in Time-Asynchronous Channels for Molecular Communications

TL;DR

This paper introduces a new time-based modulation scheme for molecular communication in time-asynchronous channels, improving detection accuracy and BER performance, especially with multiple molecules and background noise.

Contribution

The paper proposes a novel time-based modulation scheme and ML detection method for diffusion-based molecular communications with drift, enhancing performance in noisy, asynchronous environments.

Findings

Sample variance follows a noncentral chi-squared distribution.

BER improves with more information molecules released.

Proposed scheme outperforms existing methods under noise.

Abstract

In this paper, a novel time-based modulation scheme is proposed in the time-asynchronous channel for diffusion-based molecular communication systems with drift. Based on this modulation scheme, we demonstrate that the sample variance of information molecules' arrival time approximately follows a noncentral chi-squared distribution. According to its conditional probability density function (PDF), the asynchronous receiver designs are deduced based on the maximum likelihood (ML) detection, with or without background noise in the channel environment. Since the proposed schemes can be applied to the case of transmitting multiple information molecules, simulation results reveal that the bit error ratio (BER) performance improves with the increase of the number of released information molecules. Furthermore, when the background noise is not negligible, our proposed asynchronous scheme outperforms the asynchronous modulation techniques based on encoding information on the time between two consecutive release of information molecules.